But for the actions of the destroyer H.M.S. Mounsey on 6 Oct 1918, the death toll from the H.M.S. Otranto might have been a thousand.
The Mounsey was commanded by Lieutenant Francis Worthington Craven, age 29, of the British Royal Navy.
Pvt. Lonzon Sheley aboard the Otranto recalled many years later that, as the Mounsey approached even more closely, an officer aboard the Otranto— who he assumed was Captain Davidson— used a megaphone to warn Craven on the Mounsey to keep his distance. Instead, he heard Craven’s reply:
‘Be calm boys, I am coming to you.’
Craven then signaled to the Otranto:
‘Please lower your lee boats to act as fenders. I am coming alongside.’
One of the American survivors, Pvt. Charles Von Waldner, recalled later that when the small destroyer tried to come alongside the Otranto, to the hundreds of men watching, the action seemed suicidal.Many Were Held by the Sea 
The much smaller 896-ton Mounsey (vs. the 12,124-ton Otranto) was so severely damaged in the rescue operation that it did not go out on active service again.
For his actions, Lt. Craven was awarded the Distinguished Service Order (United Kingdom), the Distinguished Service Medal (United States), and the Navy Cross (United States Navy).
The citation for the Distinguished Service Order reads:
In recognition of his services when HMS OTRANTO was wrecked on the 6th October 1918. HMS OTRANTO was damaged in collision with the SS KASHMIR whilst carrying a large number of American troops. Lieutenant Craven displayed magnificent courage and seamanship in placing HMS MOUNSEY alongside HMS OTRANTO in spite of the fact that the conditions of wind, weather and sea were exceptionally severe. After going alongside and embarking a certain number of men it was reported that the MOUNSEY had sustained considerable damage, and that there was a large quantity of water in the engine room. Lieutenant Craven, therefore, left the OTRANTO but on finding the damage was not so serious as had been reported, he again went alongside, though he had previously experienced great difficulty in getting away. His action resulted in the saving of over 600 lives which would otherwise have certainly been lost. His performance was a remarkable one, and in personal courage, coolness and seamanship ranks in the very highest order.
The citation for the Distinguished Service Medal reads:
The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Army Distinguished Service Medal to Lieutenant Francis W. Craven, British Royal Navy, for exceptionally meritorious and distinguished service in a position of great responsibility to the Government of the United States, during World War I. While Commanding His Majesty’s destroyer MOUNSEY, Lieutenant Craven rescued 7 officers and 313 men of the American forces at sea on 16 October 1918.
Two other Mounsey officers were also decorated: Lt. Raymond Benson Stewart and Sub-Lt. Wilfrid Edmund Warner were awarded the Distinguished Service Cross by the British government for their heroic actions.
Note: This is post 4 of 4 today about the H.M.S. Otranto disaster.
 Many Were Held by the Sea: The Tragic Sinking of the HMS Otranto, by R. Neil Scott, Rowman & Littlefield Publishers, 18 Jun 2012.